/*
** Nofrendo (c) 1998-2000 Matthew Conte (matt@conte.com)
**
**
** This program is free software; you can redistribute it and/or
** modify it under the terms of version 2 of the GNU Library General
** Public License as published by the Free Software Foundation.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
** Library General Public License for more details.  To obtain a
** copy of the GNU Library General Public License, write to the Free
** Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
**
** Any permitted reproduction of these routines, in whole or in part,
** must bear this legend.
**
**
** map40.c
**
** mapper 40 interface
** $Id: map040.c,v 1.2 2001/04/27 14:37:11 neil Exp $
*/

#include <noftypes.h>
#include <nes_mmc.h>
#include <nes.h>
#include <libsnss.h>
#include <log.h>

#define MAP40_IRQ_PERIOD (4096 / 113.666666)

static struct
{
    int enabled, counter;
} irq;

/* mapper 40: SMB 2j (hack) */
static void map40_init(void)
{
    mmc_bankrom(8, 0x6000, 6);
    mmc_bankrom(8, 0x8000, 4);
    mmc_bankrom(8, 0xA000, 5);
    mmc_bankrom(8, 0xE000, 7);

    irq.enabled = false;
    irq.counter = (int)MAP40_IRQ_PERIOD;
}

static void map40_hblank(int vblank)
{
    UNUSED(vblank);

    if (irq.enabled && irq.counter)
    {
        irq.counter--;
        if (0 == irq.counter)
        {
            nes_irq();
            irq.enabled = false;
        }
    }
}

static void map40_write(uint32 address, uint8 value)
{
    int range = (address >> 13) - 4;

    switch (range)
    {
    case 0: /* 0x8000-0x9FFF */
        irq.enabled = false;
        irq.counter = (int)MAP40_IRQ_PERIOD;
        break;

    case 1: /* 0xA000-0xBFFF */
        irq.enabled = true;
        break;

    case 3: /* 0xE000-0xFFFF */
        mmc_bankrom(8, 0xC000, value & 7);
        break;

    default:
        break;
    }
}

static void map40_getstate(SnssMapperBlock* state)
{
    state->extraData.mapper40.irqCounter = irq.counter;
    state->extraData.mapper40.irqCounterEnabled = irq.enabled;
}

static void map40_setstate(SnssMapperBlock* state)
{
    irq.counter = state->extraData.mapper40.irqCounter;
    irq.enabled = state->extraData.mapper40.irqCounterEnabled;
}

static map_memwrite map40_memwrite[] = {{0x8000, 0xFFFF, map40_write}, {-1, -1, NULL}};

mapintf_t map40_intf = {
    40,                /* mapper number */
    "SMB 2j (pirate)", /* mapper name */
    map40_init,        /* init routine */
    NULL,              /* vblank callback */
    map40_hblank,      /* hblank callback */
    map40_getstate,    /* get state (snss) */
    map40_setstate,    /* set state (snss) */
    NULL,              /* memory read structure */
    map40_memwrite,    /* memory write structure */
    NULL               /* external sound device */
};

/*
** $Log: map040.c,v $
** Revision 1.2  2001/04/27 14:37:11  neil
** wheeee
**
** Revision 1.1  2001/04/27 12:54:40  neil
** blah
**
** Revision 1.1.1.1  2001/04/27 07:03:54  neil
** initial
**
** Revision 1.1  2000/10/24 12:19:33  matt
** changed directory structure
**
** Revision 1.9  2000/10/23 15:53:27  matt
** suppressed warnings
**
** Revision 1.8  2000/10/22 19:17:46  matt
** mapper cleanups galore
**
** Revision 1.7  2000/10/21 19:33:38  matt
** many more cleanups
**
** Revision 1.6  2000/10/10 13:58:17  matt
** stroustrup squeezing his way in the door
**
** Revision 1.5  2000/08/16 02:50:11  matt
** random mapper cleanups
**
** Revision 1.4  2000/07/15 23:52:19  matt
** rounded out a bunch more mapper interfaces
**
** Revision 1.3  2000/07/10 13:51:25  matt
** using generic nes_irq() routine now
**
** Revision 1.2  2000/07/06 02:48:43  matt
** clearly labelled structure members
**
** Revision 1.1  2000/07/05 05:05:18  matt
** initial revision
**
*/
